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Asset Retirement Obligations (Rollforward) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Asset retirement obligations at January 1 $ 2,469 $ 2,320 $ 2,197
Accretion 149 140 131
Liabilities incurred 20 27 2
Liabilities settled (17) (16) (6)
Revision in estimated cash flows 51 (2) (4)
Asset retirement obligations at December 31 2,672 2,469 2,320
DTE Electric      
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Asset retirement obligations at January 1 2,271 2,125 2,012
Accretion 138 129 120
Liabilities incurred 1 27 1
Liabilities settled (14) (8) (2)
Revision in estimated cash flows 51 (2) (6)
Asset retirement obligations at December 31 $ 2,447 $ 2,271 $ 2,125